This invention relates to a traveling device advancing and retreating along a tubular or columnar member by alternately supplying and exhausting a pressurized fluid into and from an elastic contractable body. The body is adapted to cause a contractive force in its axial direction due to radial expansion when supplied with the pressurized fluid.
In chemical plants, nuclear power stations and the like, there are a great number of pipe lines connected for chemical reaction, energy conversion processes and the like. In order to make operate these plants safely and effectively, it is necessary to maintain and inspect these pipe lines periodically. Inspection in the pipe lines is also needed, as the case may be.
However, it is sometimes impossible for an operator to directly inspect the inside of the pipe lines due to their small inner diameters and external conditions.
In such a case, damage of the pipe lines and existence or amount of substances accumulated in the pipe lines have been inspected by a traveling device having wheels or pawls and driven by an electric or hydraulic motor, which was provided with a small type television camera or fiber scope.
With such a hitherto used traveling device, as the electric or hydraulic motor is used as driving means which is probably required to have speed reduction means, the traveling device is heavy and bulky so that applicable tubes are limited. In practice, applicable tubes are limited to those of 10.sup.B -40.sup.B (JIS G3452, nominal diameters: 10"-40"). In the case of a traveling device having levers for embracing a tube line, it is exclusively applicable to only tube lines whose cross-sections are symmetrical such as circular cross-sections. In addition, such a traveling device cannot travel along an outside of a tube line due to grooves and protrusions formed on an outer surface of the tube line. Moreover, the traveling device is so heavy that it is only applicable to horizontal pipe lines or slightly inclined or curved portions of pipe lines. What is worse still, the electric or hydraulic motor as driving means tends to cause sparks and heating in operation so that the use of such a motor is disadvantageous in chemical plants including petroleum refineries treating inflammable or explosive materials.
In the case of inspecting outsides of long pipe lines or coating outer surfaces of chimneys in plants, scaffoldings are provided adjacent thereto, on which inspectors or workers stand.
However, assembling and disassembling of the scaffoldings are time-consuming and expensive operations. In addition, working on such scaffolding is often very dangerous because the scaffoldings are likely to undergo wind, vibrations and the like.